Virgil3D : a virtio based 3D GPU

Virgil3D : a virtio based 3D GPU
Dave Airlie
<[email protected]>
Red Hat, Brisbane.
Virgil3D
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Research project
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Initial implementation just to see
Focus
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Work out the 3D side of a virtio GPU
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Get familiar with virtio and qemu code
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Based on Mesa project Gallium 3D
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Linux focused
Other projects
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Vgallium
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relied on gallium drivers in host
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Old version of gallium
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Unmaintained
VirtualBox GL passthrough
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GL based is too large a surface area
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Unknown security implications
Vmware SVGAII
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Closed source
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Based on DX9 so limited capability
Components (Linux)
X.org
X.org
Mesa
Mesa
DDX
DDX
Gallium
Gallium
driver
driver
Kernel
Kernel
DRM/KMS
DRM/KMSdriver
driver
QEMU
QEMU
Renderer
Renderer
Virtio
VirtioGPU
GPU
OpenGL
OpenGL
Virtio interface
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Single virtio ring
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Context management
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3D Resource management
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Create, Destroy, Attach Resource, Detach Resource
Create, Destroy, Flush, Attach SG, Detach SG
DMA-like transfer operations
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Get, Put
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Modesetting
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Command stream submission
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Capabilities
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Fencing
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IRQ for fencing
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Config space for fencing and cursor handling
Rendering Command stream
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Gallium state objects
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Blend, rasterizer, dsa, shaders, samplers, queries etc.
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Create, bind, destroy operations
Non-state operations
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Rendering
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Framebuffer, scissor, viewport, vbos.
Draw, clear, blit
Queries
Renderer
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Convert gallium states to GL interface
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Convert TGSI shaders to GLSL shaders
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GL host context per guest context
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Required for proper conditional rendering operation
Works out capabilities from GL version and
extensions
Currently uses GLSL 1.30 shader programs
GL versions
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Guest currently at GL 2.1 + GLSL 1.20
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Host requires GL2.1 + GLSL1.30
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Up to GL3.0 in the guest mostly done
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Issues with multisample textures and
hibernate/migration
3.1 and above open a number of questions
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Lack of ARB_compatiblity
Issues
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How best to get 64-bit values back from host
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Status page seems like my best answer
How to get fence irqs?
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Second vq instead – seems like overkill
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Can a vq attach 0 elements?
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Or maybe just attach status page all the time
GL 3.x context creation
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Due to deprecated features
virtio-gpu
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Secondary project
Produce a basic virtio gpu that the virgil
renderer can attach to.
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Multi-head capable
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Unaccelerated
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PCI and VGA extras
Port QEMU to SDL 2
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SDL 2
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Multiple window support
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ARGB cursor support
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Better GL support
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EGL
Very different input
Qemu console multi-head
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Initial implementation
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Add arrays of DisplaySurfaces to QemuConsole
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Add _idx version of some interfaces
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Use SDL2 multi-window support for demo
TODO
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Howto to work out num heads limits
Beyond SDL
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Libvirt integration
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Security
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DRM render nodes
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Using EGL and dma-buf to share the final
rendered image
Viewer using GLX/EGL to composite final
rendered image
Demos
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Virgil3D rendering
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Virtio-vga multi-head